#include "cli/service/ollama_ai_service.h"

#include <cstdlib>

#include "absl/strings/str_cat.h"
#include "absl/strings/str_format.h"

// Check if we have httplib available (from vcpkg or bundled)
#if __has_include("httplib.h")
#define YAZE_HAS_HTTPLIB 1
#include "httplib.h"
#elif __has_include("incl/httplib.h")
#define YAZE_HAS_HTTPLIB 1
#include "incl/httplib.h"
#else
#define YAZE_HAS_HTTPLIB 0
#endif

// Check if we have JSON library available
#if __has_include("third_party/json/src/json.hpp")
#define YAZE_HAS_JSON 1
#include "third_party/json/src/json.hpp"
#elif __has_include("json.hpp")
#define YAZE_HAS_JSON 1
#include "json.hpp"
#else
#define YAZE_HAS_JSON 0
#endif

namespace yaze {
namespace cli {

OllamaAIService::OllamaAIService(const OllamaConfig& config) : config_(config) {
  // Load command documentation into prompt builder
  prompt_builder_.LoadResourceCatalogue("");  // TODO: Pass actual yaml path when available
  
  if (config_.system_prompt.empty()) {
    // Use enhanced prompting by default
    if (config_.use_enhanced_prompting) {
      config_.system_prompt = prompt_builder_.BuildSystemInstructionWithExamples();
    } else {
      config_.system_prompt = BuildSystemPrompt();
    }
  }
}

std::string OllamaAIService::BuildSystemPrompt() {
  // Fallback prompt if enhanced prompting is disabled
  // Use PromptBuilder's basic system instruction
  return prompt_builder_.BuildSystemInstruction();
}

absl::Status OllamaAIService::CheckAvailability() {
#if !YAZE_HAS_HTTPLIB || !YAZE_HAS_JSON
  return absl::UnimplementedError(
      "Ollama service requires httplib and JSON support. "
      "Install vcpkg dependencies or use bundled libraries.");
#else
  try {
    httplib::Client cli(config_.base_url);
    cli.set_connection_timeout(5);  // 5 second timeout
    
    auto res = cli.Get("/api/tags");
    if (!res) {
      return absl::UnavailableError(absl::StrFormat(
          "Cannot connect to Ollama server at %s.\n"
          "Make sure Ollama is installed and running:\n"
          "  1. Install: brew install ollama (macOS) or https://ollama.com/download\n"
          "  2. Start: ollama serve\n"
          "  3. Verify: curl http://localhost:11434/api/tags",
          config_.base_url));
    }
    
    if (res->status != 200) {
      return absl::InternalError(absl::StrFormat(
          "Ollama server error: HTTP %d\nResponse: %s", 
          res->status, res->body));
    }
    
    // Check if requested model is available
    nlohmann::json models_json = nlohmann::json::parse(res->body);
    bool model_found = false;
    
    if (models_json.contains("models") && models_json["models"].is_array()) {
      for (const auto& model : models_json["models"]) {
        if (model.contains("name")) {
          std::string model_name = model["name"].get<std::string>();
          if (model_name.find(config_.model) != std::string::npos) {
            model_found = true;
            break;
          }
        }
      }
    }
    
    if (!model_found) {
      return absl::NotFoundError(absl::StrFormat(
          "Model '%s' not found on Ollama server.\n"
          "Pull it with: ollama pull %s\n"
          "Available models: ollama list",
          config_.model, config_.model));
    }
    
    return absl::OkStatus();
  } catch (const std::exception& e) {
    return absl::InternalError(absl::StrCat(
        "Ollama health check failed: ", e.what()));
  }
#endif
}

absl::StatusOr<std::vector<std::string>> OllamaAIService::ListAvailableModels() {
#if !YAZE_HAS_HTTPLIB || !YAZE_HAS_JSON
  return absl::UnimplementedError("Requires httplib and JSON support");
#else
  try {
    httplib::Client cli(config_.base_url);
    cli.set_connection_timeout(5);
    
    auto res = cli.Get("/api/tags");
    
    if (!res || res->status != 200) {
      return absl::UnavailableError(
          "Cannot list Ollama models. Is the server running?");
    }
    
    nlohmann::json models_json = nlohmann::json::parse(res->body);
    std::vector<std::string> models;
    
    if (models_json.contains("models") && models_json["models"].is_array()) {
      for (const auto& model : models_json["models"]) {
        if (model.contains("name")) {
          models.push_back(model["name"].get<std::string>());
        }
      }
    }
    
    return models;
  } catch (const std::exception& e) {
    return absl::InternalError(absl::StrCat(
        "Failed to list models: ", e.what()));
  }
#endif
}

absl::StatusOr<std::string> OllamaAIService::ParseOllamaResponse(
    const std::string& json_response) {
#if !YAZE_HAS_JSON
  return absl::UnimplementedError("Requires JSON support");
#else
  try {
    nlohmann::json response_json = nlohmann::json::parse(json_response);
    
    if (!response_json.contains("response")) {
      return absl::InvalidArgumentError(
          "Ollama response missing 'response' field");
    }
    
    return response_json["response"].get<std::string>();
  } catch (const nlohmann::json::exception& e) {
    return absl::InternalError(absl::StrCat(
        "Failed to parse Ollama response: ", e.what()));
  }
#endif
}

absl::StatusOr<std::vector<std::string>> OllamaAIService::GetCommands(
    const std::string& prompt) {
#if !YAZE_HAS_HTTPLIB || !YAZE_HAS_JSON
  return absl::UnimplementedError(
      "Ollama service requires httplib and JSON support. "
      "Install vcpkg dependencies or use bundled libraries.");
#else
  
  // Build request payload
  nlohmann::json request_body = {
    {"model", config_.model},
    {"prompt", config_.system_prompt + "\n\nUSER REQUEST: " + prompt},
    {"stream", false},
    {"options", {
      {"temperature", config_.temperature},
      {"num_predict", config_.max_tokens}
    }},
    {"format", "json"}  // Force JSON output
  };
  
  try {
    httplib::Client cli(config_.base_url);
    cli.set_read_timeout(60);  // Longer timeout for inference
    
    auto res = cli.Post("/api/generate", request_body.dump(), "application/json");
    
    if (!res) {
      return absl::UnavailableError(
          "Failed to connect to Ollama. Is 'ollama serve' running?\n"
          "Start with: ollama serve");
    }
    
    if (res->status != 200) {
      return absl::InternalError(absl::StrFormat(
          "Ollama API error: HTTP %d\nResponse: %s", 
          res->status, res->body));
    }
    
    // Parse response to extract generated text
    auto generated_text_or = ParseOllamaResponse(res->body);
    if (!generated_text_or.ok()) {
      return generated_text_or.status();
    }
    std::string generated_text = generated_text_or.value();
    
    // Parse the command array from generated text
    nlohmann::json commands_json;
    try {
      commands_json = nlohmann::json::parse(generated_text);
    } catch (const nlohmann::json::exception& e) {
      // Sometimes the LLM includes extra text - try to extract JSON array
      size_t start = generated_text.find('[');
      size_t end = generated_text.rfind(']');
      
      if (start != std::string::npos && end != std::string::npos && end > start) {
        std::string json_only = generated_text.substr(start, end - start + 1);
        try {
          commands_json = nlohmann::json::parse(json_only);
        } catch (const nlohmann::json::exception&) {
          return absl::InvalidArgumentError(
              "LLM did not return valid JSON. Response:\n" + generated_text);
        }
      } else {
        return absl::InvalidArgumentError(
            "LLM did not return a JSON array. Response:\n" + generated_text);
      }
    }
    
    if (!commands_json.is_array()) {
      return absl::InvalidArgumentError(
          "LLM did not return a JSON array. Response:\n" + generated_text);
    }
    
    std::vector<std::string> commands;
    for (const auto& cmd : commands_json) {
      if (cmd.is_string()) {
        commands.push_back(cmd.get<std::string>());
      }
    }
    
    if (commands.empty()) {
      return absl::InvalidArgumentError(
          "LLM returned empty command list. Prompt may be unclear.\n"
          "Try rephrasing your request to be more specific.");
    }
    
    return commands;
    
  } catch (const std::exception& e) {
    return absl::InternalError(absl::StrCat(
        "Ollama request failed: ", e.what()));
  }
#endif
}

}  // namespace cli
}  // namespace yaze